Project description:Trypanosoma cruzi is a protozoan parasite and the etiologic agent of Chagas disease, an important public health problem in Latin America. T. cruzi is diploid, almost exclusively asexual, and displays an extraordinarily diverse population structure both genetically and phenotypically. Yet, to date the genotypic diversity of T. cruzi and its relationship, if any, to biological diversity have not been studied at the whole genome level. In this study, we used whole genome oligonucleotide tiling arrays to compare gene content in biologically disparate T. cruzi strains by comparative genomic hybridization (CGH). We observed that T. cruzi strains display widespread and focal copy number variations (CNV) and a substantially greater level of diversity than can be adequately defined by the current genetic typing methods. As expected, CNV were particularly frequent in gene family-rich regions containing mucins and trans-sialidases but were also evident in core genes. Gene groups that showed little variation in copy numbers among the strains tested included those encoding protein kinases and ribosomal proteins, suggesting these loci were less permissive to CNV. Moreover, frequent variation in chromosome copy numbers were observed, and chromosome-specific CNV signatures were shared by genetically divergent T. cruzi strains, suggesting a greater degree of chromosome exchange than previously thought.
Project description:Trypanosoma cruzi is a protozoan parasite and the etiologic agent of Chagas disease, an important public health problem in Latin America. T. cruzi is diploid, almost exclusively asexual, and displays an extraordinarily diverse population structure both genetically and phenotypically. Yet, to date the genotypic diversity of T. cruzi and its relationship, if any, to biological diversity have not been studied at the whole genome level. In this study, we used whole genome oligonucleotide tiling arrays to compare gene content in biologically disparate T. cruzi strains by comparative genomic hybridization (CGH). We observed that T. cruzi strains display widespread and focal copy number variations (CNV) and a substantially greater level of diversity than can be adequately defined by the current genetic typing methods. As expected, CNV were particularly frequent in gene family-rich regions containing mucins and trans-sialidases but were also evident in core genes. Gene groups that showed little variation in copy numbers among the strains tested included those encoding protein kinases and ribosomal proteins, suggesting these loci were less permissive to CNV. Moreover, frequent variation in chromosome copy numbers were observed, and chromosome-specific CNV signatures were shared by genetically divergent T. cruzi strains, suggesting a greater degree of chromosome exchange than previously thought. Genomic DNA samples from 16 T. cruzi strains were compared to genomic DNA from the CL Brener strain by competitive hybridizations on whole genome oligonucleotide tiling arrays.
Project description:It is well established that the pathogenicity and pathology of rabies virus (RABV) varies according to the variant, but the exact mechanism for this is still not completely known. In this study, the gene expression profile in brains of mice infected with virus isolated from a human case of dog rabies (V2) or vampire bat-acquired rabies (V3) were analyzed in experimental condition. In total, 138 array probes associated with 120 genes were differentially expressed between mice inoculated with V2 and the control mice at day 10 post-inoculation. A single probe corresponding to an unannotated gene was identified in V3 versus control mice. Gene ontology (GO) analysis revealed that all of the genes up-regulated in mice inoculated with V2 were involved in the biological process of immune defense against pathogens. Although both variants being considered pathogenic, inoculation in exactly same condition generated particular results regarding gene expression, more likely to differences in pathogenesis between dog and bat-related variants, already considered in other studies. This study was the first to demonstrate the global gene expression in experimental rabies infection due to V3 wild-type rabies virus, which reservoir is the vampire bat Desmodus rotundus, an important transmitter of rabies for humans and production animals in Latin America.